KR101300844B1 - Method for performing multiple pre-shared key based authentication at once and system for executing the method - Google Patents

Abstract

The present invention relates to a method of performing a plurality of Pre-Shared Key (PSK) based authentication at a time and a system for performing the method. In the method for performing a plurality of PSK-based authentication in a single process according to the present invention, the terminal generates a combined credential using a plurality of credentials including the user ID and the PSK. And performing authentication of the terminal by using the combined credentials in an authentication server.

Authentication, Pre-Shared Key (PSK), User ID, Latency

Description

Method for performing a plurality of PS-based authentication at a time and a system for performing the method {METHOD FOR PERFORMING MULTIPLE PRE-SHARED KEY BASED AUTHENTICATION AT ONCE AND SYSTEM FOR EXECUTING THE METHOD}

1 is a view for explaining the waiting time for two authentication in the prior art.

2 is a diagram for describing a waiting time for a plurality of authentications in embodiments of the present invention.

3 is a flowchart illustrating a method of performing a plurality of Pre-Shared Key (PSK) based authentication in a single process according to the first embodiment of the present invention.

4 is a flowchart illustrating a method of performing PSK-based authentication in a terminal according to a second embodiment of the present invention.

5 is a flowchart illustrating a method of performing PSK-based authentication in an authentication server according to a third embodiment of the present invention.

6 is a flowchart illustrating a PSK-based authentication method of a terminal and an authentication server performing PSK-based authentication in the second and third embodiments of the present invention.

FIG. 7 is a block diagram for explaining an internal configuration of a system for performing a plurality of PSK based authentication in a single process according to the fourth embodiment of the present invention.

8 is a block diagram illustrating an internal configuration of a terminal for performing PSK-based authentication according to a fifth embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

700: PSK based authentication system

710: generator

711: Combined user ID generation unit

712: combined PSK generator

713: combined credential

720: authentication unit

The present invention relates to a method of performing a plurality of Pre-Shared Key (PSK) based authentication at a time and a system for performing the method, and more particularly, the user combined the user ID and the PSK in the terminal and the user combined in the authentication server A method for performing authentication of the terminal using an ID and the PSK, and a system for performing the method.

An authentication system is a system that reliably verifies whether a user accessing a computer via a communication network is a registered or duly authorized user. Especially important in open networks, the central part of the software is the authentication server, which manages the user's name and password collectively. The authentication server verifies that the user is authorized using the encrypted authentication protocol for the program providing the service. A product of such an authentication system may be an authentication service of Xerox Network System (XNS), which is a protocol system of Xerox in the United States. Traditional Unix did not have such a system, but a Kerberos emerged, developed under the Athena Project of the Massachusetts Institute of Technology (MIT).

The authentication process of such an authentication system results in a certain latency every time it is performed. For example, challenge handshake authentication protocol (CHAP), which encrypts and transmits a simple password, requires one round-trip between the mobile device and the home domain, which results in one round-trip per authentication. There is a waiting time for it.

1 is a view for explaining the waiting time for two authentication in the prior art. As shown in FIG. 1, FIG. 1 illustrates a process of authentication request and authentication between a mobile device 101 and an authentication server 102 for two authentications, and a waiting time that occurs accordingly.

A first waiting time occurs 105 from the mobile device 101 to the authentication server 102 for a first authentication request 103 and for the authentication 104 to be made. After the authentication 104 is made, the mobile device 101 requests a second authentication from the authentication server 102 for a second authentication and a second waiting time until the authentication 107 is made. Generate 108.

As such, if a mobile device requires more than one authentication (eg separate device authentication and signature authentication), then logging in to the network would require twice the latency. This resulting latency is a major problem for seamless handover of wireless terminals.

That is, in the prior art authentication method, a plurality of independent authentications requiring transmission before the wireless terminal accesses a desired service may cause a waiting time for one authentication to be multiplied by the product of the number of authentications. When coming and going, there is a problem that handover does not occur evenly.

The present invention, in order to solve the problems of the prior art as described above, the present invention proposes a method for performing a plurality of PSK-based authentication at a time and a new technology regarding a system for performing the method.

An object of the present invention is to reduce the latency for accessing a service by the wait time for one authentication by processing a plurality of authentications through a single procedure.

Another object of the present invention is to reduce the waiting time through an authentication method using an existing authentication protocol without using a new authentication protocol.

In order to achieve the above object and to solve the above-mentioned problems of the prior art, a method for performing a plurality of pre-shared key (PSK) based authentication in a single process according to an embodiment of the present invention, the terminal Generating a combined credential using a plurality of credentials including a user ID and the PSK, and authenticating the terminal using the combined credential at an authentication server. Include.

According to one aspect of the invention, the step of generating a combined credential, generating a combined user ID by continuously combining the user ID, generating a combined PSK by continuously combining the PSK and the combined user Generating the association credential including an ID and the association PSK.

According to another aspect of the present invention, the combined user ID and the combined PSK may include the user ID and the PSK included in one credential, respectively, in the same order.

According to another aspect of the present invention, the step of generating the combined PSK by successively combining the PSK, may be performed when the authentication process of the authentication server approaches all of the PSK.

A method for performing PSK-based authentication in a terminal according to another embodiment of the present invention includes receiving a challenge code pre-selected from an authentication server, and generating a response code based on the challenge code and N PSKs. And transmitting the response code to the authentication server.

In a method for performing PSK-based authentication in an authentication server according to another embodiment of the present invention, transmitting a predetermined challenge code to a terminal, generating a first response code based on the challenge code and the N PSKs. And comparing the second response code and the first response code transmitted from the terminal, and authenticating the terminal when the second response code and the first response code are the same.

First, in the present specification, the term “terminal” refers to a personal digital cellular (PDC) phone, a personal communication service (PCS) phone, a personal handyphone system (PHS) phone, a CDMA-2000 (1X, 3X) phone, a WCDMA (Wideband CDMA) phone. Communication such as Dual Band / Dual Mode phone, Global Standard for Mobile (GSM) phone, Mobile Broadband System (MBS) phone, Digital Multimedia Broadcasting (DMB) phone, Smart phone, mobile phone, etc. Handheld devices that may include features, personal digital assistants (PDAs), hand-held PCs, notebook computers, laptop computers, WiBro terminals, MP3 players, MD players, etc., and international roaming A portable electric and electronic device, which means all kinds of handheld-based wireless communication devices, including an IMT-2000 terminal that provides a roaming service and an extended mobile communication service. Division Multiplexin g certain wireless communication devices equipped with GPS chips to enable location tracking via modules, Bluetooth modules, infrared data associations, wired and wireless LAN cards, and global positioning systems (GPS). A communication module may be provided, and the present invention may be interpreted as a generic term for a terminal capable of performing a predetermined operation by mounting a microprocessor capable of performing a multimedia playback function.

In addition, the meaning of "authenticating the terminal" or "performing the terminal" is the same as that of authenticating a plurality of user IDs to be authenticated through the terminal.

Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

2 is a diagram for describing a waiting time for a plurality of authentications in embodiments of the present invention. As illustrated in FIG. 2, FIG. 2 illustrates a process of authenticating and requesting an authentication server 202 from the mobile device 201 and waiting time accordingly.

The mobile device 201 requests a combined authentication by generating a combined user ID and a combined PSK by transmitting the user ID and the PSK required for the authentication for the plurality of authentications, respectively. In other words, the plurality of requests for authentication are resolved in one request.

In response, the authentication server 202 authenticates 204 the mobile device 201 through a single procedure for the plurality of requests for authentication, so that only a waiting time for one authentication occurs as shown (205). Done.

A method of combining the user ID and the PSK will be described in more detail with reference to the accompanying drawings.

3 is a flowchart illustrating a method of performing a plurality of Pre-Shared Key (PSK) based authentication in a single process according to the first embodiment of the present invention.

In step S310, the PSK-based authentication performing system generates a combined credential using a plurality of credentials including the user ID and the PSK in the terminal.

The Pre-Shared Key (PSK) (or shared secret) is a string of virtual private network (VPN) services that are obtained before other credentials (eg, username and password). In Windows XP, it's called pre-shared key for authentication (PSK), but in most operating systems it's known as a shared secret.

When a connection to a VPN server is created, the VPN server will not allow the authentication process until the correct string is given. If the VPN server does not receive a PSK, the username and password cannot be sent and the connection is terminated. In a sense, the PSK is a weak password, although it is not convincingly known by many people.

The PSK-based authentication performing system may configure a plurality of the credentials C including the user ID U and the PSK K as shown in Equation 1 below.

C1 = {U1, K1}, C2 = {U2, K2},... ... , Cn = {Un, Kn}

The method for generating the combined credentials using the plurality of credentials configured as in Equation 1 will be described in detail through steps S311 to S313.

In step S311, the PSK-based authentication performing system generates a combined user ID by continuously combining the user IDs. In this case, the combined user ID may distinguish the user ID through a separator including a separator such as '|', '/' or ','.

In this case, the combined user ID Uc may be expressed as in Equation 2.

Uc = U1 | ”,” | U2 | ”,” | ... ... | Un

As such, the combined user ID may be generated as a single string by listing the user IDs in a continuous string and separating the identifiers through the separator. For example, two user IDs, such as joe.smith @ ISP1.com, 00: 0D: 56: DD: C4: 49, may be generated as one string using ',' as a separator.

In step S312, the PSK-based authentication performing system continuously combines the PSKs to generate a combined PSK. This step S312 may be performed when the authentication process of the authentication server approaches all of the PSK.

In this case, the combined PSK (Kc) may be expressed as Equation 3.

Kc = K1 | K2 | ... ... | Kn

As described above, the combined PSK may be generated as one large string by concatenating the PSKs forming one string as described in step S310.

In this case, in step S311 and step S312, the combined user ID and the combined PSK may include the user ID and the PSK included in one credential in the same order.

In step S313, the PSK based authentication performing system generates the combined credential including the combined user ID and the combined PSK.

In this case, the combined credential cC may be expressed as Equation 4 below.

cC = {Uc, Kc}

As such, the combined credential cC may be expressed as a set having two strings of the combined user ID Uc and the combined PSK Kc as elements.

In step S320, the PSK-based authentication performing system performs authentication of the terminal using the combined credentials in an authentication server.

Through the combined credentials, the authentication server performs PSK based authentication and successful authentication of the combined credentials implicitly authenticates all of the plurality of credentials C1, C2, ..., Cn.

By processing a plurality of authentications through a single procedure, the latency for accessing a service can be reduced by the waiting time for one authentication, and the existing authentication protocol is not required without a new authentication protocol. By using the authentication method, the waiting time for a plurality of authentications can be reduced by the waiting time for one authentication.

However, sometimes it may not be possible to access all of the keys in a single authentication process. For example, the signature key and the device key may be stored in different hardware devices. In such a case, it is required to perform a hash on the key by an authentication method that is repeatedly performed. This method still produces proof of ownership of all PSKs, but it is certain that the PSKs do not have to be shared across security domains.

The method will be described in more detail with reference to FIGS. 4 and 5.

4 is a flowchart illustrating a method of performing PSK-based authentication in a terminal according to a second embodiment of the present invention.

In step S410, the terminal receives a challenge code pre-selected from the authentication server.

In step S420, the terminal generates a response code based on the challenge code and the N PSKs.

In step S421, the terminal converts the first PSK of the challenge code and the first user ID through a predetermined conversion method to generate a first response result. In this case, the conversion method may include a predetermined hash function.

The process of generating the first response result R1 through the challenge code ch and the first PSK K1 may be expressed by Equation 5 below.

R1 = hash (ch, K1)

In step S422, the terminal converts the n-th response result and the n-th PSK of the n-th user ID through the conversion method to generate an n-th response result.

The nth response result may be expressed as Equation 6 below.

Rn = hash (Rn-1, Kn)

In step S423, the terminal performs step S424 when n is equal to N, and performs step S422 when not equal to N. In this case, n includes a number from 2 to N, and step S423 means repeating step S422 for each of the numbers included in n.

In step S424, the terminal generates the nth response result, in which n is equal to N, as the response code.

That is, n = N means apply the hash function for PSK for all user IDs, which in turn means to generate a final response result as the response code.

In step S430, the terminal transmits the response code to the authentication server.

5 is a flowchart illustrating a method of performing PSK-based authentication in an authentication server according to a third embodiment of the present invention.

In step S501, the authentication server transmits a predetermined challenge code to the terminal.

In step S502, the authentication server generates a first response code based on the challenge code and the N PSKs.

In this case, step S502 may convert the first PSK of the challenge code and the first user ID through a predetermined conversion method to convert the first response result as described in steps S421 to S424 of FIG. 4. Generating, by the converting method, the n-th response result and the n-th PSK of the n-th user ID through the conversion method to generate an n-th response result, wherein n is equal to N; The method may further include generating a response result as the first response code. The method may further include repeating the second step for each of the numbers 2 to N included in the n.

In addition, the conversion method may include a predetermined hash function.

In step S503, the authentication server receives a second response code from the terminal.

In step S504, the authentication server compares the second response code and the first response code to perform step S505 when they are identical to each other, and ends when they are not the same.

In step S505, the authentication server authenticates the terminal when the second response code and the first response code are the same.

That is, since the authentication server owns a plurality of PSKs such as a plurality of PSKs owned by the terminal described with reference to FIG. 4, the authentication server generates a response code in advance through the method as shown in FIG. The terminal is authenticated only when compared with each other.

6 is a flowchart illustrating a PSK-based authentication method of a terminal and an authentication server performing PSK-based authentication in the second and third embodiments of the present invention.

The terminal 601 generates a response code by using the challenge code 603 transmitted by the authentication server 602 and the PSK owned by the terminal 601 (605). In addition, the authentication server 602 previously generates 604 a first response code using the same PSK that is also owned by the authentication server 602.

The terminal 601 transmits the response code to the authentication server 602, and the authentication server 602 compares the transmitted response code with the generated first response code and authenticates the terminal 601 when they are the same. 609).

If the authentication method requires a key-derivation key (KDK), the KDK may be calculated as shown in Equation 7 below.

KDKc = KDF (KDK1, KDK2 | KDKD3 | …… KDKn)

At this time, it is necessary to select an appropriate key derivation function (KDF). For example, the KDF may be expressed as Equation 8 below.

M_AES-CTR (K1, K2 | K3 | …… Kn | “Combined KDK”, ctr_iv = 1)

The KDF is a cryptographic hash function designed to make a key or password stronger.

FIG. 7 is a block diagram for explaining an internal configuration of a system for performing a plurality of PSK based authentication in a single process according to the fourth embodiment of the present invention. As shown in FIG. 7, the PSK-based authentication performing system 700 may include a generation unit 710 and an authentication unit 720.

The generation unit 710 may mean a terminal for requesting authentication, and the authentication unit 720 may mean an authentication server for authenticating the terminal. Accordingly, devices for input / output of data for authentication may be illustrated or described. Did not do it.

The generation unit 710 generates a combined credential using a plurality of credentials including a user ID and the PSK in the terminal. In this case, the generator 710 may include a combined user ID generator 711, a combined PSK generator 712, and a combined credential generator 713.

The combined user ID generator 711 continuously combines the user IDs to generate a combined user ID, and the combined PSK generator 712 continuously combines the PSKs to generate a combined PSK. In this case, the combined PSK generation unit 712 may be performed when the authentication process of the authentication server approaches all of the PSKs.

The association credential generation unit 713 generates the association credential including the association user ID and the association PSK. Since the plurality of user IDs are authenticated using the combined credentials, it is possible to authenticate the plurality of credentials with only one waiting time.

The authentication unit 720 authenticates the terminal using the combined credentials in the authentication server.

By processing multiple authentications through a single procedure through the PSK-based authentication performance system, the latency for accessing a service can be reduced by the waiting time for one authentication, and a new authentication protocol. Through the authentication method using the existing authentication protocol without the need for the need to reduce the waiting time for a plurality of authentication by the waiting time for one authentication.

For example, device authentication and signature authentication in such PSK-based authentication systems are expected to exist in a common place in WiMAX networks. World Interoperability for Microwave Access (WiMAX) is a technology approach Intel is developing to target technology standards for the mobile Internet. Complementing the existing wireless LAN (802.11a / b / g) technology to greatly widen the Internet use radius outside the building, there is a disadvantage that does not guarantee the handoff between the base station and the base station when moving.

According to this initial provision of WiMAX, the terminal of the WiMAX will be required to authenticate both the device authentication and the signature authentication on the same authentication server.

Applying the present invention to such WiMAX can reduce the login waiting time to the WiMAX network in half.

In addition, the handover of the mobile terminal can be evenly used using this. Handover means that the mobile terminal is automatically tuned to a new call channel of a neighboring base station continuously when the mobile station in a call moves out of the cell boundary to the neighboring base station service area. It means the function to keep the call state.

In this case, the call disconnection time while the call channel is automatically switched is about 15 ms or less. During such a short period of time, the base station and the terminal perform a digital message communication, making it difficult for a subscriber who is busy to detect an instantaneous disconnection.

However, if the waiting time is longer, the disconnection time may be further increased, which may result in a great inconvenience for the subscriber.

As described above, the above-described problems can be solved by reducing the waiting time through the present invention.

8 is a block diagram illustrating an internal configuration of a terminal for performing PSK-based authentication according to a fifth embodiment of the present invention. As illustrated in FIG. 8, the terminal 800 may include a challenge code input unit 810, a generator 820, and a response code transmitter 830.

The input unit 810 receives a challenge code pre-selected from the authentication server. The value of the challenge code may be predetermined by the authentication server.

The generation unit 820 generates a response code based on the challenge code and the N PSKs. In this case, the generation unit 820 may include a first response result generation unit 821, an nth response result generation unit 822, a response code generation unit 823, and an iteration unit 824.

The first response result generator 821 generates a first response result by converting the first PSK of the challenge code and the first user ID through a predetermined conversion method.

The n-th response result generator 822 converts the n-th response result and the n-th PSK of the n-th user ID through the conversion method to generate an n-th response result.

The response code generator 823 generates the nth response result, in which n is equal to N, as the response code.

The method of generating the response code may be performed through the same method as the method of generating the response code described with reference to FIG. 4.

The repeater 824 repeats the n-th response result generator for each of the numbers included in n.

The response code transmitter 830 transmits the response code to the authentication server.

As described above with reference to FIGS. 2 through 8, an authentication method for authenticating a user ID may be performed by separate authentication servers. For example, although multiple credentials may be included in the same mobile terminal, each may be authenticated by a separate AAA (Authorization, Authentication and Accounting) server. In this case, a new authentication protocol (eg, a new Extensible Authentication Protocol (EAP) method) and an AAA-based protocol (eg, RADIUS (Remote Authentication Dial-In User Service)) can be solved through extension.

Embodiments according to the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical media such as CD-ROMs, DVDs, and floppy disks. Magneto-optical media, and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. The medium may be a transmission medium such as an optical or metal line, a wave guide, or the like, including a carrier wave for transmitting a signal designating a program command, a data structure, or the like. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

As described above, the present invention has been described by specific embodiments such as specific components and the like. For those skilled in the art, various modifications and variations are possible from these descriptions.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

According to the present invention, by processing a plurality of authentication through a single procedure (procedure), the latency (latency) for accessing the service can be reduced by the waiting time for one authentication.

According to the present invention, the waiting time can be reduced through an authentication method using an existing authentication protocol without using a new authentication protocol.

Claims (21)

In the method of performing a plurality of Pre-Shared Key (PSK) based authentication in a single process, Generating a combined credential using a plurality of credentials each including one user ID and one PSK in the terminal; And Performing authentication of the terminal using the combined credentials in an authentication server; PSK-based authentication performing method comprising a. The method of claim 1, The step of generating a binding credential, Generating a combined user ID by successively combining the user IDs included in the plurality of credentials; Generating a combined PSK by successively combining the PSKs included in the plurality of credentials; And Generating the combined credential including the combined user ID and the combined PSK. PSK-based authentication performing method comprising a. 3. The method of claim 2, PSK-based authentication, characterized in that the user ID and the PSK included in the i-th credential of the plurality of credentials respectively correspond to the i-th user ID of the combined user ID and the i-th PSK of the combined PSK. How to do it. 3. The method of claim 2, The step of generating the combined PSK by continuously combining the PSK, PSK-based authentication method, characterized in that performed when the authentication process of the authentication server approaches all of the PSK. 3. The method of claim 2, The combined user ID distinguishes user IDs included in the plurality of credentials through a predetermined identifier. The delimiter comprises a delimiter of '|', '/' or ',' PSK-based authentication method. In the method for performing PSK-based authentication in the terminal, Receiving a predetermined challenge code from an authentication server; Generating a response code based on the challenge code and the N PSKs; And Sending the response code to the authentication server Including, The N is PSK-based authentication method characterized in that the natural number of two or more. The method according to claim 6, Generating a response code based on the challenge code and the N PSKs, A first step of converting the first PSK of the challenge code and the first user ID through a predetermined conversion method to generate a first response result; A second step of generating an n-th response result by converting the n-th response result and the n-th PSK of the n-th user ID through the conversion method; And If n is equal to N, generating the nth response result as the response code PSK-based authentication performing method comprising a. The method of claim 7, wherein N includes a number from 2 to N, Repeating the second step for each of the numbers included in n PSK-based authentication method characterized in that it further comprises. The method of claim 7, wherein And the conversion method comprises a predetermined hash function. In the method of performing Pre-Shared Key (PSK) based authentication in the authentication server, Transmitting a predetermined challenge code to the terminal; Generating a first response code based on the challenge code and the N PSKs; Receiving a second response code from the terminal; Comparing the first response code and the second response code; And Authenticating the terminal if the first response code and the second response code are the same; Including, The N is PSK-based authentication method characterized in that the natural number of two or more. The method of claim 10, Generating a first response code based on the challenge code and the N PSKs, A first step of converting the first PSK of the challenge code and the first user ID through a predetermined conversion method to generate a first response result; A second step of generating an n-th response result by converting the n-th response result and the n-th PSK of the n-th user ID through the conversion method; And If n is equal to N, generating the nth response result as the first response code PSK-based authentication performing method comprising a. 12. The method of claim 11, N includes a number from 2 to N, Repeating the second step for each of the numbers included in n PSK-based authentication method characterized in that it further comprises. 12. The method of claim 11, And the conversion method comprises a predetermined hash function. A computer-readable recording medium in which a program for executing the method of any one of claims 1 to 13 is recorded. In a system that performs multiple PSK-based authentication in a single process, A generation unit for generating a combined credential using a plurality of credentials each including one user ID and one PSK in the terminal; And Authentication unit for authenticating the terminal using the combined credentials in the authentication server PSK-based authentication performing system comprising a. 16. The method of claim 15, The generation unit, A combined user ID generation unit generating a combined user ID by sequentially combining the user IDs included in the plurality of credentials; A combined PSK generation unit for generating a combined PSK by successively combining the PSKs included in the plurality of credentials; And A combined credential generation unit generating the combined credential including the combined user ID and the combined PSK, PSK-based authentication, characterized in that the user ID and the PSK included in the i-th credential of the plurality of credentials respectively correspond to the i-th user ID of the combined user ID and the i-th PSK of the combined PSK. Carry system. 17. The method of claim 16, The combined PSK generation unit, And the authentication process of the authentication server is performed when all of the PSKs are accessed. In the terminal performing PSK-based authentication, A challenge code input unit which receives a challenge code pre-selected from the authentication server; A generator configured to generate a response code based on the challenge code and the N PSKs; And Response code transmitter for transmitting the response code to the authentication server Including, The N is PSK based authentication terminal, characterized in that more than two natural numbers. 19. The method of claim 18, The generation unit, A first response result generator configured to convert the first PSK of the challenge code and the first user ID through a predetermined conversion method to generate a first response result; An n-th response result generation unit for generating an n-th response result by converting the n-th response result and the n-th PSK of the n-th user ID through the conversion method; And A response code generation unit generating the nth response result as the response code when n is equal to N; PSK-based authentication performing terminal comprising a. 20. The method of claim 19, N includes a number from 2 to N, The nth response result generator, PSN-based authentication performing terminal, characterized in that for each of the number included in the n, repeatedly generating the n-th response result. 20. The method of claim 19, The conversion method PSK donation authentication terminal, characterized in that it comprises a predetermined hash function (hash function).

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